Express your answer as a mixed number simplified to lowest terms. $15\dfrac{10}{18}-8\dfrac{8}{18} = {?}$
Answer: Separate the whole numbers from the fractional parts: $= {15} + {\dfrac{10}{18}} - {8} - {\dfrac{8}{18}}$ Bring the whole numbers together and the fractions together: $= {15} - {8} + {\dfrac{10}{18}} - {\dfrac{8}{18}}$ Subtract the whole numbers: $=7 + {\dfrac{10}{18}} - {\dfrac{8}{18}}$ Subtract the fractions: $= 7+\dfrac{2}{18}$ Combine the whole and fractional parts into a mixed number: $= 7\dfrac{2}{18}$